Worcester County District Attorney Joseph D. Early Jr.'s announcement on Saturday wasn't surprising: One day before, Early had said the body wrapped in a blanket and stuffed inside a bag matched the height and weight of Jeremiah.

Still, how he got there and even how he died is still unknown. The district attorney did not detail a cause of death Saturday, explaining the child's autopsy is not yet complete.

The case raised questions about the state's role as it relates to Jeremiah's care, with Massachusetts Department of Children and Families Commissioner Olga Roche admitting that there had been "a serious failure."

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"We are deeply saddened by the tragic loss of Jeremiah Oliver" Roche said Saturday. "DCF continues to focus on caring for Jeremiah's siblings to ensure they are receiving the support they need during this very difficult time."

In March, Jeremiah's mother, 28-year-old Elsa Oliver, and her boyfriend, 22-year-old Alberto Sierra, were indicted by a grand jury on charges related to Jeremiah's disappearance as well as on charges of child abuse. Calls to the attorneys for both were not immediately returned Friday.

The district attorney's office did not speculate Saturday on whether they might face additional charges now that Jeremiah has been confirmed dead.

The last documentation of state authorities' interaction with Jeremiah was in May 2013, according to Department of Children and Families spokesman Alec Loftus.

In June, Loftus said, the social worker was told that Jeremiah had moved to Florida to live with his grandmother but did not follow up or verify that.

The last visit to the home was in November, when the social worker left behind a business card indicating it would be the Department of Children and Families' final visit, according to Loftus.

On December 2, Jeremiah's 8-year-old sister told counselors at her elementary school that her mother's boyfriend, Sierra, had abused her, according to a police affidavit.

After those statements, the girl and another brother were taken into protective custody, according to the affidavit.

It was in December that authorities realized that the boy was missing.

Roche fired the social worker and supervisor assigned to his case because they did not conduct the required in-person, monthly checks on the family, according to a statement released that month.